Why should you care?

Less typing for small helpers. Teams use them in array methods like map and filter.

See it live — copy this example

Paste into an HTML file or the browser console (F12). Use Run below when the live editor is available.

const double = (n) => n * 2;
console.log(double(4));

const sum = (a, b) => {
  return a + b;
};
console.log(sum(2, 3));

Run Example »

Edit the code below and click Run to see the result in Toolliyo’s live editor.

What happened?

• If the body is one expression, you can omit return and braces.
• Multiple lines need { return ...
• }.

Practice next

1. Run double and sum examples.
2. Rewrite greet as an arrow function.
3. Use [1,2,3].map(x => x * 2) in the console.
4. Return an object from an arrow function using parentheses: () => ({ ok: true }).
5. Use an arrow in setTimeout and log this — compare with function() {}.

Remember

(param) => expression Add { } and return for multiple lines Great for short callbacks

ScriptVerse filter pipeline

Product lists use arrow callbacks in filter and map for concise transformation chains.

Outcome: Arrow functions keep array processing readable in modern React and vanilla JS codebases.